Can balneology cure what ails you?

The most well-known of Iceland's natural hot springs, the Blue Lagoon is arguably the world's most famous hydrothermal bath.
(Photo: Robert Hoetink/Shutterstock)

It was the monkeys that convinced me; the hot springs-loving snow monkeys of Japan that love to chill in thermal springs made me a believer in the power of the soak.

Of course, monkeys aren't the only creatures that like to hang out in geothermal pools. They're not the only animals: capybaras, dogs and some cats enjoy warm baths; bears, elephants, horses and birds regularly bathe in lakes and rivers. For humans, public baths and bathing rituals are common in many cultures around the world, and some public baths have been in use for hundreds of years.

When I visit new places, I seek out historic and "locals only" baths. I've spent time in natural thermal baths in Bath, England; Weisbaden, Germany; Arenal, Costa Rica; central Mexico, and most recently on the tiny Caribbean island of Nevis (see below). I've also visited wild hot springs on the Big Island of Hawaii, the Oregon mountains and El Salvador. Iceland's Blue Lagoon and Japanese hot springs are high on my list of "must-dips."

Throughout history, people have taken to public baths to relax, and in some cases, to socialize. (In many places, community baths still serve as a local gathering spot.) But almost all baths purport to have health benefits, from the logical easing of aches and pains, to less obvious cures like addressing skin conditions, asthma, arthritis, high blood pressure and more. This bathing for health benefits is called balneology.

Usually the healing benefits of natural springs are attributed to minerals found in the water, which are picked up as the water passes through rocks as it makes its way to the surface. These minerals can include calcium, sulfate, magnesium, iron, chloride, potassium, zinc, salts and often hydrogen sulfide, which people might refer to as "sulphur" and which smells kind of like rotten eggs — though not nearly as bad, in my opinion.

Can there be real health benefits from balneology? The short answer is that experts aren't sure. According to the Journal of Epidemiology, which looked at the results of several studies, researchers said, "We found evidence that aquatic exercise had small but statistically significant effects on pain relief and related outcome measures of locomotor diseases (eg: arthritis, rheumatoid diseases, and low back pain). However, long-term effectiveness was unclear." Part of that lack of clarity stems from the varying quality of the studies.

Bathing in the Jigokudani onsen has become a winter routine for many local monkeys. (Photo: Sorin Colac/Shutterstock)

But as Stephanie Lee writes in Lifehacker about her own hot spring bathing experience in Japan, at least some of the health benefits of hot springs are likely part of the communal and stress-reducing aspects of the practice — not so much the waters themselves. "We don’t get super strong or fit from just a single workout, nor do we suddenly reverse years of eating crap by eating a single piece of fruit. So it’s probably safe to say the real benefits of hot springs come from habitual use, as part of a holistic approach to health."

This understanding of the bathing ritual makes sense, as researchers continue to connect chronic stress to a variety of health issues. Rituals that physically and mentally reduce stress, as baths do, mean that over time, people who engage in them experience less stress — and likely feel better for it.